Nanodecoy system: A novel approach to design hepatitis B vaccine for immunopotentiation

Activation of NLRP3 Inflammasome Complexes by Beta-Tricalcium Phosphate Particles and Stimulation of Immune Cell Migration in vivo

Beta-tricalcium phosphate (β-TCP) serves as a bone substitute in clinical practice because it is resorbable, biocompatible, osteointegrative, and osteoconductive. Particles of β-TCP are also inflammatory mediators although the mechanism of this function has not been fully elucidated. Regardless, the ability of β-TCP to stimulate the immune system might be useful for immunomodulation. The present study aimed to determine the effects of β-TCP particles on NLR family pyrin domain containing 3 (NLRP3) inflammasome complexes. We found that β-TCP activates NLRP3 inflammasomes, and increases interleukin (IL)-1β production in primary cultured mouse dendritic cells (DCs) and macrophages, and human THP-1 cells in caspase-1 dependent manner. In THP-1 cells, β-TCP increased also IL-18 production, and NLRP3 inflammasome activation by β-TCP depended on phagocytosis, potassium efflux, and reactive oxygen species (ROS) generation. We also investigated the effects of β-TCP in wild-type and NLRP3-deficient mice in vivo. Immune cell migration around subcutaneously injected β-TCP particles was reduced in NLRP3-deficient mice. These findings suggest that the effects of β-TCP particles in vivo are at least partly mediated by NLRP3 inflammasome complexes.

Cell-Membrane-Mimicking Nanodecoys against Infectious Diseases

Infectious diseases are a leading cause of mortality worldwide, with viruses and bacteria in particular having enormous impacts on global healthcare. One major challenge in combatting such diseases is a lack of effective drugs or specific treatments. In addition, drug resistance to currently available therapeutics and adverse effects caused by long-term overuse are both serious public health issues. A promising treatment strategy is to employ cell-membrane mimics as decoys to trap and to detain the pathogens. In this Perspective, we briefly review the infection mechanisms adopted by different pathogens at the cellular membrane interface and highlight the applications of cell-membrane-mimicking nanodecoys for systemic protection against infectious diseases. We also discuss the implication of nanodecoy-pathogen complexes in the development of vaccines. We anticipate this Perspective will provide new insights on design and development of advanced materials against emerging infectious diseases.

Stealth lipid coated aquasomes bearing recombinant human interferon-α-2b offered prolonged release and enhanced cytotoxicity in ovarian cancer cells

PURPOSE

In present investigation, recombinant human interferon-α-2b (rhINF-α-2b) loaded aquasomes were prepared, optimized and overlaid with PEGylated phospholipid to offer prolong release and high therapeutic index against ovarian cancer, SKOV3 cells.

METHODS AND RESULTS

Central Composite Design (CCD) and Response Surface Methodology (RSM) were employed to calculate the optimized conditions, 1:3 core to coat ratio, sonication power of 12.5W and time of about 55min for preparation of aquasomes. Consequently, rhINF-α-2b-Py-5-P-Aq.somes exhibited higher protein loading capacity and retained structural conformations of rhINF-α-2b, as compared to rhINF-α-2b-Cellob-Aq.somes, rhINF-α-2b-Tre-Aq.somes and rhINF-α-2b-Core (CaHPO4). Further, optimized rhINF-α-2b-Py-5-P-Aq.somes was superimposed with phospholipid-PEG2000 to prolong the release pattern of rhINF-α-2b from aquasomes. The rhINF-α-2b-core (CaHPO4) released 97.3% of protein in 1h, while 95.3% of rhINF-α-2b was released by rhINF-α-2b-Tre-Aq.somes in 4h. Concurrently, rhINF-α-2b-Cellob-Aq.somes and rhINF-α-2b-Py-5-P-Aq.somes released 96.2% and 97.8% of rhINF-α-2b respectively in 6 and 8h. Ultimately, rhINF-α-2b-Py-5-P-Aq.somes-P-PEG2000 displayed evidence of its prolonged release pattern and released 98.1% of rhINF-α-2b in 336h. FT-IR and XRD substantiated the involvement of vigorous intermolecular hydrogen bonding and amorphous geometry in rhINF-α-2b-Py-5-P-Aq.somes. In last, rhINF-α-2b-Py-5-P-Aq.somes-P-PEG2000 exhibited the∼4.55, 1.92, 2.3, 2.8, and 3.84 fold reductions in IC50 as compared to free rhINF-α-2b, rhINF-α-2b-Py-5-P-Aq.somes, rhINF-α-2b-Cellob-Aq.somes, rhINF-α-2b-Tre-Aq.somes and rhINF-α-2b-Core (CaHPO4), respectively.

CONCLUSION

Therefore, rhINF-α-2b-Py-5-P-Aq.somes-P-PEG2000 warrant further in depth in vitro and in vivo antitumor study to scale up the technology for clinical intervention.

Advances in effective vaccine development against hepatitis B: focus on mucosal vaccine delivery strategies

Hepatitis B virus causes chronic necroinflammatory liver disease, which is known as hepatitis B. This inflammatory condition may further aggravate liver cirrhosis or hepatocellular carcinoma. Currently available conventional hepatitis B vaccine contains one of the viral envelope proteins, hepatitis B surface antigen, which develops a humoral immune response and hence protects against the infection. However, it fails in developing the desired cellular immune response, which is one of the most important bioresponses contributing to virus elimination from infected hepatocytes. At the same time, moderate humoral response developed following conventional vaccination do not protect the mucosal surfaces through serosal response. The mucosa is a predominant entry site for most of the infectious pathogens. Several strategies, including the use of adjuvants, development of surface functionalized novel antigen carriers and mucosal immunization for example, have been explored to investigate their role in addressing the limitations associated with the current hepatitis B vaccine. This review focuses on recent advances that have been made in order to develop an effective vaccine against hepatitis B.

Alginate coated chitosan nanoparticles are an effective subcutaneous adjuvant for hepatitis B surface antigen

We recently described a delivery system that is composed of a chitosan core to which the hepatitis B surface antigen (HBsAg) was adsorbed and subsequently coated with sodium alginate. In this present work, alginate coated chitosan nanoparticles were evaluated as a subcutaneous adjuvant for HBsAg. HBsAg loaded, alginate coated or uncoated chitosan nanoparticles, associated or not with CpGODN were subcutaneously administered to mice and several immunological parameters were evaluated. A high anti-HBsAg IgG titer (2271+/-120 mIU/ml), with the majority of antibodies being of Th2 type, was observed within group I, vaccinated with HBsAg loaded onto coated nanoparticles. However, regarding cellular immune response, no significant differences were observed for antigen-specific splenocyte proliferation or for the secretion of IFN-gamma and IL-4, when compared to the control group. The co-delivery of antigen-loaded nanoparticles in the presence of the immunopotentiator, CpG ODN 1826, resulted in an increase of anti-HBsAg IgG titers that was not statistically different from the first group; however, an increase of the IgG2a/IgG1 ratio from 0.1 to 1.0 and an increase (p<0.01) of the IFN-gamma production by the splenocytes stimulated with the HBV antigen was observed. The enhancement of the immune response observed with the antigen-loaded nanoparticles demonstrated that chitosan is a promising platform for parenteral HBsAg delivery and, when co-administered with the CpG ODN, resulted in a mixed Th1/Th2 type immune response.